There are two types of parachute systems in general use today, for large scale users, such as military organizations. One type features the circular/hemispherical, generally ballistic, parachutes, having very little capability for traversing an air mass, and the other features the high performance, inflatable wing, parafoils that require highly sophisticated guidance and control devices, or highly skilled parachutists, to operate reliably.
Generally speaking, both the ballistic and high glide types of parachute systems must be kept in inventory, and operations managers must chose between one or the other, because the systems are not interchangeable and there is no system to bridge the gap between the two.
While it is much less costly to fabricate a circular/hemispherical type parachute than a parafoil type parachute, of the same general size, construction of the circular/hemispherical type of parachute is, nevertheless, not especially efficient when the amount of fabric used in the construction is considered. A typical circular/hemispherical type parachute canopy is generally constructed from multiple triangular gore panels that radiate from a central point, and is depicted by FIG. 6. Generally, the gore panels are truncated to provide the parachute canopy with a centrally located vent and, occasionally, the triangular gore shape is slightly modified to provide a more aerodynamically appropriate shape for a specific application. Extending outward from the canopy skirt, generally from the radial seams that join the gores, are suspension members with a length that generally approximate the constructed diameter of the canopy.
When properly inflated, the circular/hemispherical type parachute canopy will be reduced around its entire circumference, resulting in a projected diameter that is reduced by approximately one third of its constructed diameter. An undesirable consequence of a circular/hemispherical canopy that has been effectively reduced by approximately 33.3% of its constructed diameter is that it projects a drag area that has been reduced by approximately 44.4% of its constructed area. The outermost circle of FIG. 4 illustrates the constructed area of a circular/hemispherical type parachute canopy and the shaded portion of the figure depicts the relative inflated size. Additionally, the circular/hemispherical parachute has very little capability for altering its ballistic path to enable it to reach a specific target.
Parafoil type parachute canopies are multiple cell, airfoil shaped, ram-air inflatable, wings made of many complex panel shapes requiring demanding fabrication processes. To establish the rigging angle necessary to achieve a desired glide angle, and maintain the desired airfoil shape, great variation in the length of the suspension lines is necessary, depending on their designated locations. When properly inflated, a parafoil type parachute has a generally rectangular, or elliptical, plan form, and, quite frequently, has a span that is approximately 250% of its chord. While parafoils have very impressive flight characteristics, if not properly controlled during flight, they can miss their intended targets by huge amounts and, if not properly controlled at landing, can severely damage delivered payloads and injure or kill parachutists.
It is therefore an object of the invention to provide a novel parachute design that will efficiently fulfill all the performance requirements of the low cost, low performance, circular/hemispherical type parachute and many of the requirements of the high cost, high performance, parafoil type parachute with a simple to construct, low cost, parachute.
It is another object of the invention to provide a parachute having a canopy with a generally rectangular plan form.
It is another object of the invention to provide a parachute having inverted-gores.
It is another object of the invention to provide a parachute having canopy segments.
It is another object of the invention to provide a parachute having longitudinal seams.
It is another object of the invention to provide a parachute having, downwardly converging, suspension lines.
It is another object of the invention to provide a parachute having riser assemblies.
It is another object of the invention to provide a parachute having canopy end panels.
It is another object of the invention to provide a parachute that is selectively ballistic or gliding.
It is another object of the invention to provide a parachute that is selectively steerable.
It is another object of the invention to provide a parachute with a selectively variable descent rate.
It is another object of the invention to provide a parachute with efficient materials utilization.